JEE 2022 — Mathematics PYQ
JEE | Mathematics | 2022Let Δ∈{∧,∨,⇒,⇔} be such that (p∧q)Δ((p∨q)⇒q) is a tautology. Then Δ is equal to:
Choose the correct answer:
- A.
∧
- B.
∨
- C.
⇒
(Correct Answer) - D.
⇔
⇒
Explanation
Solution
1. Simplify the second part of the expression:
-
The expression (p∨q)⇒q is equivalent to ∼(p∨q)∨q.
-
Using De Morgan's Law: (∼p∧∼q)∨q≡(∼p∨q)∧(∼q∨q)≡(∼p∨q)∧T≡(∼p∨q).
-
This is further equivalent to p⇒q.
2. Test the options for (p∧q)Δ(p⇒q):
-
If Δ is ⇒: (p∧q)⇒(p⇒q).
-
Since p∧q implies both p and q, and q alone implies p⇒q (as T⇒T is T), the entire implication is a tautology.
Correct Option: (C)
Explanation
Solution
1. Simplify the second part of the expression:
-
The expression (p∨q)⇒q is equivalent to ∼(p∨q)∨q.
-
Using De Morgan's Law: (∼p∧∼q)∨q≡(∼p∨q)∧(∼q∨q)≡(∼p∨q)∧T≡(∼p∨q).
-
This is further equivalent to p⇒q.
2. Test the options for (p∧q)Δ(p⇒q):
-
If Δ is ⇒: (p∧q)⇒(p⇒q).
-
Since p∧q implies both p and q, and q alone implies p⇒q (as T⇒T is T), the entire implication is a tautology.
Correct Option: (C)

